Trace levels of bromacil detected in two Oahu water systems

Honolulu – Trace levels of the chemical bromacil were recently detected in water samples collected at a Mililani Wells III pump and a Waipio Heights Wells III pump during testing prior to placing these pumps into service. Drinking water from these wells remains safe as the trace levels detected were well below the Environmental Protection Agency (EPA) Lifetime Advisory Level for drinking water, and bromacil will be filtered out through the Honolulu Board of Water Supply’s Granular Activated Carbon (GAC) treatment facilities before being delivered to consumers.

“These trace levels of chemicals are so small they do not pose a public health threat and the water filtered from these wells is safe to drink,” said Keith Kawaoka, Deputy Director for Environmental Health. “The Department of Health will continue to work together with the Honolulu Board of Water Supply, to ensure tests for these chemicals continue as part of the rigorous process of scheduled monitoring regularly conducted to ensure that everyone’s water is safe and public health is not compromised.”

The bromacil level confirmed at the Mililani Wells III pump was 0.24 parts per billion and the level at the Waipio Heights Wells III pump was 0.23 parts per billion. These trace levels are more than one hundred times lower than the EPA Lifetime Health Advisory Level for bromacil of 70 parts per billion, which is measured in micrograms per liter. EPA defines the Lifetime Health Advisory Level as the concentration in drinking water that is not expected to cause any adverse, non-carcinogenic effects for a lifetime of exposure.

Bromacil is a broad-spectrum herbicide used for weed control for pineapple fields and citrus plants.

The Honolulu Board of Water Supply conducts tests at sources and treatment facilities as mandated by federal and state drinking water regulations. To date, the Mililani and Waipio Heights water systems continue to be in full compliance with all federal and state standards for drinking water.